1. Field of the Invention
The present invention relates generally to a photo-voltaic apparatus, and more particularly, to a photo-voltaic apparatus in which an inverter is integrated into a photo-voltaic module, to output an alternating current (AC).
2. Description of the Prior Art
In recent years, a photo-voltaic apparatus located outdoors for generating photo-voltaic power has been paid attention to from the globally environmental problem, and the photo-voltaic apparatus has been installed on a roof so that power generated by the photo-voltaic apparatus compensates for consumed power in the daytime.
Generally, the photo-voltaic apparatus is formed as a photo-voltaic module having suitable dimensions in order to make the manufacture thereof easy and make transportation to the location thereof easy. As shown in FIG. 28, a required number of photo-voltaic modules 102 are located on a located frame 101. Each of the photo-voltaic modules 102 is provided with a terminal box 103 in order to electrically connect the modules 102 to each other and take out an output.
Since power generated by the photo-voltaic module 102 is a direct current (DC) output, the output must be converted into an alternating current (AC) for use in a household power supply. As shown in FIG. 29, outputs of the plurality of photo-voltaic modules 102 are integrated, an output obtained by the integration is fed to a connection box 104, and a direct current output is fed to an inverter 105 from the connection box 104. The direct current output is converted into an alternating current in the inverter 105, and the alternating current is supplied to a home-use load 107 from a panel board 106. Further, power is also supplied from a commercial power system 108 to the home-use load 107. The power can be utilized from the power system 108 in a case where power supplied from the photo-voltaic apparatus is insufficient during the night, for example.
As described in the foregoing, the photo-voltaic apparatus generates a direct current output. In order to change the direct current output into an alternating current output, an independent inverter is required. Since this type of inverter has been conventionally developed for a household power supply, a system of several kilowatts is at the center thereof. Therefore, the power of the photo-voltaic module must be integrated depending on the capability of the inverter. In the conventional photo-voltaic apparatus, therefore, there are problems. For example, a minimum of approximately 6 m.sup.2 is required as the light receiving area, and the location of the photo-voltaic apparatus is restricted.
Furthermore, a control circuit, a power circuit, and the like are respectively constructed as integrated circuits, and an inverter unit into which the integrated circuits are integrated is published. An alternating current output can be obtained from one photo-voltaic module by using the inverter unit.
The surface temperature of the photo-voltaic apparatus reaches not less than approximately 70.degree. C. at the time of fine weather in midsummer, and its heat is transferred to the reverse surface of the photo-voltaic apparatus, so that the temperature of the reverse surface is also increased. When the inverter unit is directly located on the reverse surface of the photo-voltaic apparatus, therefore, the inverter unit is heated by heat generated by the photo-voltaic apparatus, which prevents heat from being self-radiated, resulting in reduced conversion efficiency. Further, the inverter unit may, in some cases, be broken by the heat generated by the photo-voltaic apparatus.